1. Field of the Invention
The present invention relates to a linear motor having an air bearing integrally, and more particularly, to a linear motor having an air bearing for guiding the linear motion of a separately constructed linear motor integrally.
2. Description of the Related Art
Generally, in a linear motor including a stator and a mover, it is necessary that the stator is spaced from the mover at a constant interval in order to directly perform a linear motion. In addition, an air bearing for guiding a precise linear motion is used.
The construction and operation of a conventional linear motor having an air bearing will now be described with reference to the accompanying drawings. FIG. 1 is a side cross-sectional view illustrating the construction of a conventional linear motor and a conventional air bearing. As illustrated in FIG. 1, the linear motor 10 and the air bearing 20 are installed on the bottom surface of a frame 30, being separated from each other at a predetermined interval. The linear motor 10 includes a stator S and a mover M and the air bearing 20 includes an inverted xe2x80x9cUxe2x80x9d shaped frame 21 and a guide block 22.
The stator S of the linear motor 10 has a xe2x80x9cUxe2x80x9d shaped frame 11 and a plurality of permanent magnets 12. The permanent magnets 12 are installed on inner walls of the xe2x80x9cUxe2x80x9d shaped frame 11 at a predetermined interval. The mover M is installed internally in the stator S having the xe2x80x9cUxe2x80x9d shaped frame 11 and the permanent magnet 12, and has a straight line type frame 13 and an armature coil 14. The armature coil 14 is installed on the bottom surface of the straight line type frame 13, i.e., xe2x80x9cxe2x88x92xe2x80x9d shaped type. When a thrust force is generated by the interaction between the permanent magnets 12 installed on the inner walls of the xe2x80x9cUxe2x80x9d shaped frame at the predetermined interval and the armature coil 14, the mover M performs a linear motion in the longitudinal direction of the stator S.
In the case that the mover M performs the linear motion in the longitudinal direction of the stator S, the air bearing 20 is used for keeping a constant interval between the stator S and the mover M or for smoothly stopping the linear motion. The air bearing 20 is constructed such that the inverted xe2x80x9cUxe2x80x9d shaped frame 21 is installed to protect the guide block 22 fixedly installed on the ground. The air bearing 20 having the inverted xe2x80x9cUxe2x80x9d shaped frame 21 and the guide block 22 and the linear motor 10 are installed on the bottom surface of the frame 30.
The linear motor 10 is constructed such that the straight line type frame 13 is installed on the bottom surface of the frame 30, and the air bearing 20 is constructed such that the inverted xe2x80x9cUxe2x80x9d shaped frame 21 is installed on the bottom surface of the frame 30, for thereby supporting the linear motor 10 by the air bearing 30. In order to support the linear motor 10 by the air bearing 20, air is injected into an air supplying pipe 32 in an arrow direction via an air through hole 31 through which the installation surfaces of the frame 30 and the inverted xe2x80x9cUxe2x80x9d shaped frame 21 are penetrated.
As described above, in the conventional linear motor and air bearing, the thrust force of the linear motor is degraded by installing a separate frame in order to connect the linear motor and the air bearing. In addition, with an asymmetric structure, the rigidity and precision of the linear motor are degraded when a linear motion is conducted by means of the air bearing connected at one side of the linear motor, and a step difference equal to a height h is generated when the linear motor and the air bearing are installed, for thereby causing inconveniency in the installation.
It is, therefore, an object of the present invention to provide a linear motor having an air bearing integrally.
It is another object of the present invention to provide a linear motor which have a symmetric structure in the linear motion, can be structured simply and can be removed a step difference equal to a height generated when the air bearing and the linear motor are installed.
It is another object of the present invention to provide a linear motor that since the air bearing is formed integrally with the linear motor, the linear motor can be cooled using the air applied to the air bearing.
To achieve the above object, there is provided a linear motor having an air bearing integrally comprising: a xe2x80x9cUxe2x80x9d shaped frame having a plurality of permanent magnets spaced from each other on its inner walls; an inverted xe2x80x9cUxe2x80x9d shaped frame spaced from outer walls of the xe2x80x9cUxe2x80x9d shaped frame at a predetermined interval, having extension frames for protecting the xe2x80x9cUxe2x80x9d shaped frame and having a plurality of air injection openings for injecting air into both ends of a center frame; and an armature coil unit installed on the bottom surface of the inverted xe2x80x9cUxe2x80x9d shaped frame and the center frame and spaced from the permanent magnets installed to the inner walls of the xe2x80x9cUxe2x80x9d shaped frame at a predetermined interval.
In addition, at least one inverted xe2x80x9cUxe2x80x9d shaped frame is installed in the longitudinal direction of the xe2x80x9cUxe2x80x9d shaped frame, an air supplying pipes for receiving air from the outside and injecting the same is installed to the air injection openings formed at both ends of the center frame of the inverted xe2x80x9cUxe2x80x9d shaped frame, and the air supplied to the air injection openings of the inverted xe2x80x9cUxe2x80x9d shaped frame is supplied between the armature coil unit and the plural permanent magnets.